


What you make it

by onceuponachildhood



Series: (Currently unnamed ut human au) [1]
Category: Undertale (Video Game)
Genre: Additional characters tagged as they appear, Alternate Universe - Human, Family Issues, Gen, Nonbinary Character, Spoilers, unlikely friendship
Language: English
Status: In-Progress
Published: 2015-10-30
Updated: 2015-11-02
Packaged: 2018-04-28 22:49:42
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,423
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5108486
Author URL: https://archiveofourown.org/users/onceuponachildhood/pseuds/onceuponachildhood
Summary: <blockquote class="userstuff">
              <p>Sans thought his life was complicated enough without adding a kid to the mix. | aka in which Sans accidentally adopts a monster as a second sibling.</p>
            </blockquote>





	1. he's no zatanna, that's for sure

**Author's Note:**

> loosely based on [toddnet](http://toddnet.tumblr.com/)’s human au, mostly the designs (([this pic](http://toddnet.tumblr.com/post/131651958905/its-actually-a-piggyback-ride-because-i-couldnt) in particular ruined me but you should go look at all of todd’s amazing stuff)) but a little of the relationship dynamics; 110% based on the fact that i love big sibling instinct fics so much  
> jfc i meant for this to be like, maybe 1000 words, tops. now look where we are.

* * *

Someone was crying in the alleyway. **  
**

Sans didn’t stop, necessarily. Crying in an alleyway could mean several things, and approximately zero of them were good. Sans was no hero; he’d be the first to tell you that. But the alleyway was just ahead on the right. And he was tired, walking home from his shift. Real tired. Slowing his pace wasn’t out of the question. He let his shoulders slouch some more, his hands already shoved into the pockets of his ubiquitous hoodie. His fingers brushed the blade kept hidden in the left pocket. He hoped he wouldn’t need it.

A voice, low and angry and slurred, called out “-come here, you little freak!” followed by a high-pitched noise like a child’s cry. Welp. If there was a kid involved, he couldn’t just leave the situation be.  _You really should_ , said the little voice in his head, but since when was he intent on following directions? Sans stepped around the corner.

There was somebody huddled in the corner of a wall and a dumpster, arms held over their head protectively. Their shoulders shook as they cried - definitely the high, thin wail of a child, though they looked a little bigger than he’d expected. Presumably, the source of the angry voice was the asshole stumbling toward them with a broken bottle clutched in hand. Welp. Sans sighed internally. He just had to butt in.

Externally, he kept his slouch, but he stepped into the alleyway in a decisive way that belied his relaxed posture. “Hey!” Both the asshole and the kid cowering looked at him. He kept his tone casual despite the raised volume. “Just what the hell do you think you’re doing there, bucko?”

“This- this  _freak_  made me drop my shit!” The asshole gestured wildly to the kid with the bottle, but his attention was firmly on Sans.  _Good._  “Fucking look at this monster. Fucking talking cow or some bullshit.”

The kid shrank further into a ball, pulling their hat down as best they could. Sans caught a glimpse of something between the edges of the kid’s glove and the hem of their sleeve, but it was too dark to really tell other than that it was snowy white. Sans held his ground as the asshole advanced; he could smell the overpowering scent of alcohol on the guy’s breath. That was… something he could use to his advantage, actually. He let the fist clenched in his left pocket go and thumbed open the hidden flap in his right pocket instead, snagging a small powdery ball in his fingers.

The guy got close enough that he towered over Sans, which was his first mistake. “Sounds like you’ve been drinking too much.” Sans pulled the ball from his hoodie, rolled it around in his fingers down below where the asshole was looking until he could strike the side of it with his thumbnail. “No such thing as talking cows. You been hittin’ the bottle a little hard today,  _bucko_?” He tossed the ball down as hard as he could without making the motion obvious. Smoke started slowly billowing up from his feet. He glared up at the guy with his brow furrowed. It was easier to make his face look shadowed with the asshole’s height. At this angle, with the smoke and his heterochromia visible even in the shitty lighting, he probably looked more than a little intimidating. “All I see is some drunk who’s gonna get his balls busted for harassing some kid, unless he fucks the fuck off… right  _now_.”

The guy took a couple of stumbled steps back from him, and Sans grinned. It wasn’t a friendly one. His breath curled around him like the smoke. “I- I-” the guy took another stumbling step backward before throwing himself as far to the right of Sans and he could and bolting.

The alley was silent except for the sound of whimpering.

Sans shifted his attention back to the kid, kicking the slowly dying smoke-bomb behind him and out of the alley. The kid was sniffling, now, still trying to hide beneath their jacket and hat. His steps were slow and easy, loud enough that the kid could hear him coming “Hey,” he said, crouching down so that his face was level with the kid’s. “My name is Sans. You okay?”

The kid shook their head.

Sans looked them over - what he could see, at least. There was blood on the sleeve of their jacket, and smeared along the wall behind them. Their dress was ripped a bit at the bottom, and he could see where the asshole had probably tried to cut the kid’s boot with the bottle. “You hurt anywhere else, or just on your arm?”

The kid hiccuped, shoulders shaking.

Was that a yes or a no? Sans crouched next to the kid until his legs burned with the effort. “Hey, kid,” he tried to talk as gently as possible, like he might after Papyrus woke up from a nightmare. “What’re you doing alone out here? Where’s your parents?”

At that, the kid looked up. The first thing that Sans noticed was that the kid was definitely  _not_  human. They had white fur and a long, sort of… goatlike snout? The second was that their eyes, peeking from the bangs of a messy brown mop, were just a shade off from Papyrus’s. Those same eyes were filling with tears at an alarming pace.

The kid lunged forward, throwing their arms around Sans and outright  _bawling_. He dropped a knee to the gritty alley floor to balance them out. Shit. “Hey, hey, it’s okay.” He settled his arms around them loosely - not wanting them to feel trapped but also wanting to offer a little comfort. He’d always been tender when Paps cried, too. It was easy, from there, to rub a soothing hand on their back. The kid just started crying harder, burying their face in Sans’s hoodie. “It’s okay. You’re okay.”

They shook their head.

Sans bit back a sigh and waited until the shuddering tears subsided into watery eyes and the occasional hiccup. When the kid seemed… well, not okay, but settled enough to talk, he leaned back to look them in the eye. Definitely goat, he thought. The kid’s hat had been knocked askew from their embrace and he could see little nubs of horns poking out from the kid’s hair. The kid looked back at him just as curiously; Sans’s timely rescue and easy smile were clearly putting them a little more at ease. At least, he aimed for an easy smile. “You got a name, kid?” The kid nodded but looked down at the ground. Ah. “Not much for talking, huh?”

They shook their head.

Nonverbal was something Sans was used to, even if he wasn’t exactly happy about it. He let out a slow, even breath. “Do you know sign language?” he asked. His was a bit rusty, but he could manage. Probably. The kid shook their head again, slumping a little.

Time to change subject, then. “How old are you, kid?”

The kid held up nine fingers. Sans wondered what their hands looked like under the gloves.

“Still a little young to be walking the city by yourself, yeah?” The kid hunched their shoulders, looking back down at the ground. “Eh, don’t worry about it. I used to do stupid shi- stuff when I was nine too.” The kid peeked up at him through their bangs and managed a shy smile. Sans grinned back. “Do you know how to get home?” A fast headshake this time. Sans was getting into delicate territory here. “Do you, uh, have a home?”

The kid nodded fiercely, something finally in their eyes other than tears. Indignation, maybe.

Sans held up his hands in a surrendering gesture. “Just checking, kiddo.” The kid had no way of getting home, at least not that night, and their wince when they moved reminded him that they were injured in at least one place. He couldn’t just leave them there. That was low, even for him. And he couldn’t take them to the hospital or police station or anything- god, he could just imagine the shitstorm that would follow. “Maybe we should get your arm cleaned up, kid.” He stood, thighs protesting every movement, and held a hand out to them. “If you don’t mind coming with me, that is.”

The kid shot up, only letting out a little gasp at what was most likely pain. They grabbed his hand and held it like a life preserver. Like he would change his mind and leave if they let go. With their free hand, they straightened out their hat and readjusted their scarf so it covered their nose. What he could see of their face looked suddenly very determined. “You ready?” he asked. The kid looked so damn serious, he couldn’t help the amusement in his tone.

The kid gave him one decided nod.

* * *

The house was quiet when they stepped in, Sans pulling the key out of the door and dropping it back in his pocket. Papyrus would be staying the night at Undyne’s, since they’d gone to a con and would get back late enough to just sort of go straight to bed. Sans had no idea where his dad was, and he frankly didn’t care.

He closed the door behind them and led the kid through the house and up the stairs. The kid still held tightly onto his hand but glanced curiously around the house. “Trying to unravel the mysteries of my house, kiddo?” The kid grinned up at him, even if it was still a little watery. “You’re, uh, gonna have to hang out in my room for a bit. I don’t know when anyone else will be home.”

The kid shrugged. They were probably used to having to hide from people.

Sans led the kid into his room. He would have apologized for the mess but he honestly wasn’t sorry. That was  _his_  space. He could treat it how he wanted. And the kid didn’t seem to mind, in any case. They finally let go of his hand to sit on the bed. “I’m gonna get the first aid kit from the bathroom, okay?” There was a glimmer of panic in the kid’s eyes, but also that same determination he’d seen earlier. “I’ll be right back.”

He stepped out into the hallway and resisted the urge to slump against the wall. There was a strange kid in his room. Strange as in stranger, strange as in somehow a sentient goat child, strange as in Sans was probably in  _way_ over his head. He sighed. He was too soft about kids, man. It didn’t help that this particular kid had Papyrus’s same brand of sweet, earnest eyes. Everyone knew how big of a softie Sans was about his little bro. Way over his head he might have been (oh, he was; he fucking knew he was), but at least he knew a fair amount of first aid. Patch the poor kid up? That he could do.

-

The kid was still sitting patiently on the bed, but their head swiveled to look at Sans as soon as he made it back to the door, a look of pure relief on their face. Oh, he was  _absolutely_  in way over his head. “Told you I’d be right back,” he said, keeping his tone light. And maybe a little teasing. He had a strange feeling the kid would take it well.

The kid stuck their tongue out at him. But, they were definitely smiling. One point for Sans.

He set the first aid box down. A quick glance at the kid’s arm told him what he’d suspected - the blood from their arm was dried to the fabric. “We’re gonna have to get your jacket off,” he explained. “It’s… probably gonna hurt.”

The kid nodded, not looking phased. They didn’t even wait for Sans to help before they began peeling the sleeve away from their wound. Their teeth gritted- it had to hurt like a bitch- but other than a little huff they didn’t make any noise. With a shrug, they pulled the jacket off the rest of the way and dropped the thing on the floor, blood side up. They were wearing a sleeveless dress under the jacket, which Sans was glad for. Bringing a strange goat child home with you to patch up was one thing, but asking them to strip in your room was a whole level of weird he didn’t want to think about.

It also gave him better access to the nasty-looking gash on the kid’s arm. The drunk had clearly gotten a lucky swipe in with the broken bottle, and Sans actually regretted not escalating the situation to physical violence. Sans eyed the wound with sympathy. It wasn’t gonna be bad enough to need stitches, he thought, but he would still butterfly it closed before putting gauze on it.

The kid drew in a big breath and let it out shakily from their mouth. “You ready, kiddo?” They nodded and shifted sideways on the bed so that Sans could better reach their arm.

He sat down and took their arm as gently as he could. Their fur was soft, almost downy. Maybe it was because they were so young; he’d have expected goat fur to be a little rougher. Sans turned their arm so he could get a good look at their wound. There was no glass or anything in it, for which he was immensely grateful. Picking glass out of a wound was one thing; picking glass out of a wound on a kid was another level of hell entirely. He took an alcohol wipe and carefully wiped the edges of the gash, just to be sure they were good and clean. He dug around in the first aid box until he found a couple of butterfly bandages. Hopefully they would stick to the fur well enough to do their job without being too painful to remove.

The kid watched almost curiously as he pulled the edges of the wound together and held them together with the bandages. “It’ll heal up better that way,” he explained. “Less obvious scarring, too.”

The kid shrugged with their free shoulder. A gloved hand reached up and gently tapped Sans’ cheek under his left eye. The scar there wasn’t terrible, but it was the most obvious one he had.

Sans snorted. “Yeah, like that. You think that one is bad, you should have seen it before it was bandaged.” The kid wiggled a little, eyes wide in a clearly questioning manner. “Mm, yeah I think that story’s gonna have to wait, champ.” He snagged the gauze and started wrapping it carefully around the kid’s arm. Just enough to keep it clean while it healed; it wasn’t bleeding anymore and he didn’t want to smother it. He used a little medical tape to hold it closed, and then grinned at the kid. “You took that like a pro, kid.” They beamed brightly at the praise.

Silence fell for a moment. Sans leaned his back against the wall and toed his shoes off in the general direction of the corner, and after a second’s hesitation the kid followed suit. They tugged off their scarf and gloves and dropped them somewhere near the head of the bed. Sans glanced over at the kid. They looked from their ungloved hands to Sans, and then they grinned like a lightbulb had gone off in their head. The kid gestured like they were writing.

“You want a pen and paper, huh?” The kid nodded emphatically. Sans let out a dramatic huff and stood, giving the kid a wry look. “I’ll get you some  _write_  away.”

For a second the room was dead silent. Then, the kid let out a sharp, startled laugh that sounded almost like a bleat. Sans snickered. The kid flushed a little, but they still giggled with him. Sans found a mostly-unused notebook on his desk (he didn’t even bother taking the couple of pages of notes out of the front; they were just idle quantum physics theories, nothing he seriously needed around) and grabbed a pencil from where it was still sitting in the sharpener.

The kid took the notebook from him with a surprising solemnity. They turned it to the first blank page back and jotted something down. After a moment, they turned the notebook around and gave Sans a genuine, bright smile.

The page simply read  _Frisk_. The kid held their paw out for a handshake, still beaming.

“Frisk, huh?” They nodded again. Sans smiled back and shook their paw. “Nice to meet ya, Frisk.” 

* * *

 

**Notes for the Chapter:**

> Why does Sans have a hidden pocket in his hoodie? I promise it'll be explained later in the fic, but the chapter title might be an obscure hint at the reasoning.


	2. fraternal feelings

* * *

Sans was nice.

Frisk was very glad he’d found them in the alley. Things had been scary- almost as scary as leaving the Underground- and then he’d shown up like a comic book hero. They were still feeling a little starry-eyed about it, to be honest, so when he’d said he had to step out for a little bit and for Frisk to _stay put_ , they stayed put.

He’d left when somebody had come back to the house. The sound of the door shutting had been only slightly louder than the sudden clacking of dogs’ nails on the floor. Sans’s face had darkened a little when whoever came in with the dogs, but he still took the time to ruffle Frisk’s hair before he left. They’d appreciated the gesture.

Frisk glared down at the notebook in their lap. They’d been entertaining themselves by drawing. They’d already drawn the handful of people in pictures on Sans’s desk, and now they were drawing Sans from the alley. But something was… wrong with it. Frisk rested their chin in their paws, smudging pencil along the fur of their cheek. The drawing was almost perfect. They’d gotten the sharp shadows, the soft wispiness of the smoke (they’d smudged it with their paw, which was how they were now smearing it all over their cheek), but there was something still missing.

His eye! Frisk thought, and that was exactly it. They took their still-smudged paw pad and used the leftover graphite to carefully color his left eye. It looked as wispy and dangerous as the smoke, and Frisk smiled. That was it. That was exactly what they wanted. Frisk yawned and glanced over at the alarm clock. Sans hadn’t been gone more than an hour, but it was late… and Frisk had had a definitely more difficult day than usual. They yawned again, fighting the downward pull of their eyelids. Maybe a short nap wouldn’t be so bad.

* * *

The sound of knocking on the door woke Frisk. They sat up blearily, rubbing their eyes, just in time to see the door swing open. “Sans! We had to leave early ‘cause Alphys… got… sick…” The stranger stumbled to a stop in his words and his walking. He blinked at Frisk with wide brown eyes. Frisk blinked back, feeling suddenly very much awake. “You’re not Sans.”

Frisk stared at him, not really sure what they should do. He looked kinda familiar, though they couldn’t figure out why...

He looked about as confused and unsure as Frisk felt, and that actually made them feel a little better. He shuffled from foot to foot, rubbing the back of his neck. “Are you, um,” he sounded unsure too. Frisk felt suddenly very warm toward him; he just seemed… nice. He coughed. “Are you a friend of Sans’s?”

It might be too soon to say yes. But Sans had rescued them. And bandaged them up. They nodded.

The stranger relaxed, like Frisk being a friend of Sans’s was an immediate green light. “I’m Papyrus,” he said cheerfully. His smile made Frisk want to smile back. “Sans is my older brother.”

Brothers, they were brothers- Frisk’s head whipped toward the desk. Papyrus was in most of the pictures! He looked so familiar because they’d already drawn him a couple of times.

Papyrus followed their line of sight, and his grin got wider. “Ah, yes, Sans keeps pictures of his very cool and very popular brother around to inspire him!” Papyrus posed heroically, one fist on his hip and another on his chest. His eyes shone in the light. His grin was almost blinding. He looked… _so cool_.

Frisk immediately grabbed the discarded notebook and pencil and started drawing him exactly like that. He looked like a superhero- Frisk wouldn’t expect anything else from Sans’s brother- and they wanted to capture the moment. Their paw flew across the page. They were so intent on their work that they didn’t notice Papyrus had moved until he sat down next to them to look at the page.

“What are you drawing?”

Usually having a stranger so close to them would make Frisk uneasy. But they looked up at Papyrus and his smile- his face looked natural with a smile on it, Frisk thought- and gave him a slightly cheeky grin back before they turned back to the page. They angled the book just a little so that it was easier for Papyrus to watch. It made it harder to draw, but Frisk found that they really didn’t mind. Papyrus was silent, an eager audience as the lines on the page began to take shape. He didn’t seem to mind, either, that Frisk had so suddenly ended their conversation and turned to their sketchbook. In the Underground there had been many monsters who’d hated it when Frisk did that. Papyrus acted like it was completely normal, though, and it soothed Frisk more than they expected. Papyrus felt... safe. They didn’t know how to say this, though, and so they focused on showing just how cool this new person was.

About halfway into the drawing, Papyrus gasped. “It’s me!” He sounded so surprised, so happy, that Frisk grinned even though they didn’t look away from the page. “You’re drawing me!”

Frisk continued drawing, tuning everything else out except for the swish of fur brushing across the book, and the soft striking of graphite on paper. It didn’t take long before they were done. It was a little more sketchy than they would have liked, but it was definitely Papyrus standing in the spotlight. Suddenly feeling very shy, Frisk tipped the page toward their subject and carefully kept their gaze on their own lap.

Papyrus was silent long enough that Frisk chanced looking up at him. He was beaming so widely it almost looked like his eyes had tears in them. “This is so very good!” Papyrus looked from the notebook to Frisk’s face, and they quickly ducked their head again. Just because mom was super happy when they drew pictures of her didn’t mean that someone else would be. But Papyrus seemed more than happy. “I look almost as cool as I do in real life,” Papyrus continued. “My tiny friend, thank you so much! I love it! You are a very good artist.”

He… liked it? Better than that, he _loved_ it. He’d called Frisk his _friend_. They suddenly felt like blushing.

Papyrus gently tapped their paw clutching onto the notebook. “Have you drawn anything else?”

Frisk nodded.

“Oh!” Papyrus bounced a little in place. “May I see them?”

Swallowing, Frisk nodded. They passed the notebook over, feeling shy again. They couldn’t watch as Papyrus flipped through their sketches of the photos- smiling faces Frisk had no name for, but they’d looked so happy that Frisk couldn’t not draw them- and when he gasped again Frisk didn’t want to look at where he’d stopped.

“This…” Papyrus seemed to be at a loss for words. Frisk glanced at him from under their bangs. His expression was indescribable. Frisk thought maybe it was something between awe and shock. “This is Sans.”

He’d found the alley drawing. Frisk peeked at the page just to be sure, and then looked away as they nodded.

Papyrus was silent for a long time. Frisk finally looked at him, at his puzzled expression. He was steadily staring at the drawing they’d done. “He looks like a hero, come to save the day when everything looks bleak,” Papyrus said carefully.

He had it exactly! Somehow, he knew exactly what Frisk had been trying to convey. They nodded fiercely. Frisk shifted so that they could brandish their arm at Papyrus, nearly shoving the bandages under his nose.

“Tiny friend, you are hurt!” Papyrus sounded so genuinely concerned for them. Frisk felt another burst of warmth. “Sans took care of you though.”

Frisk nodded again.

After a minute, Papyrus smiled again. It looked a little sadder than before, a little softer, but no less real. “That’s my big brother. He’s my hero too.” Frisk grinned. “Do you, um-” Papyrus faltered. He rubbed the back of his neck again with his free hand. “... I don’t know your name, tiny friend.”

Frisk didn’t try to take the notebook back, but instead reached across Papyrus to flip the pages back to their name.

“Ah! Your name is Frisk!” They nodded, just to make sure he knew he was right. “Well, um, Frisk…” Papyrus wrinkled his nose. “Um.” He sounded suddenly almost… nervous? Frisk watched him fidget, and he looked anywhere but where they were sitting.

Frisk took a chance and laid a paw on Papyrus’s arm. He jumped a little bit, like he was startled, but he didn’t pull away. Their gesture must have comforted him some, because he looked almost immediately calmer. “I was wondering if you might… might let me keep the drawing of Sans?” He wanted to keep it? “I… He looks _right_ , all heroically drawn like this.”

The love in Papyrus’s voice was clear to Frisk. Suddenly feeling determined, they pulled the notebook from Papyrus’s hands. A look of rejection crossed his face for a split second, but he covered it with a smile pretty quickly. Frisk felt bad that they’d made him feel bad, but that was fixable enough. They carefully tore the page with the drawing of Sans out of the notebook and held it outstretched to Papyrus.

He really let everything he was feeling show on his face. The gratitude and joy in his expression made Frisk feel like they were on top of the world. They wanted suddenly, fiercely, to be his friend. Papyrus took the drawing, and Frisk pretended not to notice his hands shaking a little. “Thank you, tiny friend Frisk.”

They patted his arm and smiled. He seemed to understand them just fine.

* * *

 

**Notes for the Chapter:**

> still sussing out some characterization here; if you have any comments, criticisms, or suggestions, please let me know! i welcome concrit and also i thank you all for reading. this au already holds a place near and dear to my heart.


End file.
